JP2008044477A - Caster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a caster enabling movement of a movement table by less energy. <P>SOLUTION: When drive force is applied, the movement table 200 is moved relative to a support table 300. A spherical member 102 is rotated by friction force with the movement table 200. Since a movement amount of the movement table 200 is twice a movement amount of the spherical member 102, the spherical member 102 is moved in a direction opposite to a movement direction relative to the movement table 200. The spherical member 102 is moved to apply a pressure to a pressure transmission member 104. A truncated cone-like coil spring 103 is arranged on a periphery of the pressure transmission member 104 and is resistant to the pressure from the spherical member 102 transmitted through the pressure transmission member 104. Since the truncated cone-like coil spring 103 is the one having a small wire diameter and a sufficiently small initial modulus of transverse elasticity, resistant force applied from the truncated cone-like coil spring 103 to the spherical member 102 becomes small. Namely, friction force between the spherical member 102 and the pressure transmission member 104 becomes small and traveling resistance of the movement table 200 is reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a caster using, for example, a spherical rolling member.

  Conventional casters are known which are provided between a moving body and a support body, that is, between the moving table and the support table, and support the moving table with respect to the support table. Such a caster has a spherical rolling member that contacts the moving table and the support table to support the moving table, a holding member that holds the rolling member, and the rolling member to the supporting table via the holding member. And mainly holding members.

The restraining member is in sliding contact with the rolling member with a contact area that can resist the pressure applied from the rolling member. Thereby, the structure which prevents the movement of a rolling member is known (patent document 1).
JP 2004-291214 A

  However, when the moving table moves, a first friction force (rolling friction) is generated between the moving table and the support table and the rolling member. The first frictional force acts on the suppressing member, and further generates a second frictional force (sliding friction) between the suppressing member and the rolling member. This second frictional force becomes a large running resistance of the moving table. On the other hand, the first frictional force that causes the generation of the second frictional force increases in proportion to the weight of the moving table. Therefore, the running resistance increases in proportion to the weight of the moving table.

  The present invention reduces the contact area between the rolling member and the member in contact with the rolling member and suppresses the movement of the rolling member using an elastic member to reduce the frictional force, thereby reducing the running resistance of the moving body. The object is to obtain a caster that is small and enables movement of a moving body with less energy.

  The caster according to the present invention supports the movable body so as to be movable in one or two directions with respect to the support body, and the movable body and the support body have opposing surfaces facing each other, and are parallel to the direction in which the movable body moves. In addition, the cross section in a plane perpendicular to the facing surface is circular, and the rolling member that supports the moving body and the facing surface of the supporting body in contact with the rolling member, and suppresses the movement of the rolling member in the moving direction of the moving body. It is characterized by comprising an elastic member.

  The elastic member is preferably in contact with the rolling member at the most protruding portion of the rolling member in the moving direction of the moving body, and a pressure transmission member may be provided between the rolling member and the elastic member.

  When the caster supports a movable body movable in one direction, the rolling member is preferably cylindrical, and a pressure transmission member is preferably provided between the rolling member and the elastic member. .

  The rolling member is preferably spherical.

  The pressure transmission member provided between the rolling member and the elastic member has a cylindrical shape whose axial length is shorter than the diameter of the rolling member and whose inner diameter is longer than the diameter of the rolling member. Preferably, the rolling member is perpendicular to the support, and the rolling member is disposed inside the pressure transmission member.

  The elastic member may be a coil spring, and more preferably a frustoconical coil spring.

  The axial length of the coil spring is preferably the same length as the radius of the rolling member.

  The large-diameter end portion having the largest diameter in the truncated conical coil spring may be fixed to the moving body or the support body so that the central axis of the coil spring is perpendicular to the moving body.

  A pressure transmission member is provided between the rolling member and the truncated conical coil spring. The pressure transmission member has an axial length shorter than the diameter of the rolling member and an inner diameter longer than the diameter of the rolling member. It is preferably cylindrical and provided inside the frustoconical coil spring so that the central axes of the frustoconical coil spring and each other are substantially coaxial, and the rolling member is preferably arranged inside the pressure transmission member.

  The moving body or the support body includes a support member that protrudes around the rolling member in the moving direction of the moving body with a certain distance, and the coil spring is provided between the rolling member and the supporting member, and the moving body moves. It is desirable to suppress the movement of the rolling member by contacting the rolling member at the most protruding portion of the rolling member in the direction.

  The elastic member may be a leaf spring, and the moving body or the support body includes a supporting member that protrudes around the rolling member in the moving direction of the moving body with a certain distance, and the leaf spring is a rolling member and It is preferable to suppress the movement of the rolling member by being provided between the support members and contacting the rolling member at the most protruding portion of the rolling member in the moving direction of the moving body.

  The support body is made of a magnetic material, and a magnet may be attached to the moving body. The moving body may be made of a magnetic material, and a magnet may be attached to the support.

  According to the present invention, it is possible to obtain a caster that enables the moving body to move with a small running resistance.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  A first embodiment will be described with reference to FIGS. In FIG. 4, the nut 106 that fixes the caster 100 is omitted for the sake of explanation.

  The casters 100 according to the present embodiment are positioned between the moving body, that is, the moving table 200 and the supporting body, that is, the support table 300, and are fixedly provided with nuts 106 at the four corners of the moving table 200 one by one.

  The support table 300 and the moving table 200 are flat rectangular parallelepipeds. Opposing surfaces 111 and 112 facing each other are formed smoothly and are provided in parallel to each other.

  The caster 100 is a spherical rolling member, that is, a spherical member 102, an elastic member 103 that suppresses the movement of the spherical member 102 in the moving direction of the moving table 200, and a position between the spherical member 102 and the elastic member 103. And a cylindrical pressure transmission member 104.

  In FIG. 3, the ball member 102 is in contact with the moving table 200 at the upper part and is in contact with the support table 300 at the lower part. Thereby, the ball member 102 supports the moving table 200 with respect to the support table 300.

  The pressure transmission member 104 has a cylindrical shape, and is provided between the moving table 200 and the support table 300 so that the center axis is perpendicular to the moving table 200 and passes through the approximate center of the ball member 102. A ball member 102 is placed inside the pressure transmission member 104.

  The axial length of the pressure transmission member 104 is shorter than the diameter of the ball member 102. As a result, a clearance is secured between the pressure transmission member 104 and the moving table 200 so that they do not come into contact with each other, and the pressure transmission member 104 does not generate a frictional force with respect to the movement of the moving table 200. On the other hand, the end of the pressure transmission member 104 on the support table side contacts and slides on the support table 300 due to gravity. Further, the inner diameter of the pressure transmission member 104 is longer than the diameter of the ball member 102. Therefore, a clearance can be secured between the ball member 102 and the pressure transmission member 104, and the ball member 102 is not completely restrained by the pressure transmission member 104.

  The end and inner surface of the pressure transmission member 104 are covered with a material having a small friction coefficient. By reducing the friction coefficient of the surface that may contact or come into contact with the ball member 102, the support table 300, and the moving table 200, it is possible to reduce the frictional force due to the contact and reduce the running resistance of the moving table 200.

  The elastic member 103 is a coil spring having a frustoconical outer shape, that is, a frustoconical coil spring 103, around the pressure transmission member 104 so that the winding center axis of the coil and the central axis of the pressure transmission member 104 are substantially coaxial. Provided. The large-diameter end 108 having the largest diameter of the truncated conical coil spring 103 is fixed to the moving table 200 so that the center axis is perpendicular to the moving table 200. A clearance is secured between the inner periphery of the small-diameter end portion 109 having the smallest diameter and the pressure transmission member 104. Due to the pressure transmission member 104, the truncated conical coil spring 103 and the spherical member 102 do not contact each other. Since the inner surface of the pressure transmission member 104 is covered with a material having a small friction coefficient, the frictional force can be made smaller than when the frustoconical coil spring 103 and the ball member 120 are in direct contact with each other.

  The axial length of the truncated conical coil spring 103 is substantially half of the diameter of the spherical member 102. Therefore, the small-diameter end portion 109 is located at a portion of the pressure transmission member 104 corresponding to the most protruding portion of the ball member 102 in the moving direction of the moving table 200. As a result, the force applied from the ball member 102 to the pressure transmission member 104 and the force applied from the truncated conical coil spring 103 to the pressure transmission member 104 are opposed to each other via the pressure transmission member 104. Since the force from the spherical member 102 and the truncated conical coil spring faces each other, the axis of the pressure transmission member 104 does not tilt with respect to the axis perpendicular to the movable table 200, so that the pressure transmission member 104 collides with the movable table 200 or No extra resistance is generated between 120 and the support table 300.

  The moving table 200 and the truncated conical coil spring 103 are fixed by locking the large-diameter end portion 108 between the moving table 200 and the four support members 105 attached to the moving table 200.

  The support member 105 has a shape in which one corner of the rectangular parallelepiped is cut out in a direction in which a cylinder axis and one side of the rectangular parallelepiped are parallel to each other by a cylinder having substantially the same diameter as the large-diameter end portion 108, and protrudes toward the moving table 200. A screw part 107 is provided. A groove portion 110 having a depth substantially the same as the wire diameter of the truncated cone coil spring 103 is formed on the plane of the support member 105 on the side of the moving table 200 in the vicinity of the circular arc formed by cutting with a circular cylinder. The frustoconical coil springs are locked by fitting the large-diameter end portion 108 to the groove portion 110 at four locations on the circumference of the large-diameter end portion 108 and equally arranged in the circumferential direction. The screw portion 107 protrudes from a surface opposite to the caster 100 through a through hole 203 formed in the moving table 200. The screw part 107 protruding on the opposite surface of the caster 100 in the moving table 200 is screwed into the nut 106. As a result, the support member 105 is fixed to the moving table 200, the large-diameter end portion 108 is sandwiched between the support member 105 and the moving table 200, and the truncated conical coil spring 103 is fixed to the moving table 200.

  Three magnets 202 are provided on the surface of the moving table 200 facing the support table 300 using an adhesive or a screw (not shown). The magnets 202 are located near both ends of one side of the moving table 200 and at the center of the side facing the one side. The support table 300 is made of a magnetic material, and the moving table 200 is attracted to the support table 300 by a magnetic force and is restrained in the vertical direction with respect to the support table 300.

  Due to the action of the magnet 202 and the support table 300 made of a magnetic material, the support table 300 and the moving table 200 are not separated even if the moving table 200 according to the present embodiment is not provided perpendicular to gravity. .

  Next, the operation of each member when the moving table 200 moves relative to the support table 300 will be described with reference to FIG. For the sake of explanation, it is assumed that the ball member 102 does not slide between the moving table 200 and the support table 300.

  When a driving force is applied to the moving table 200, the moving table 200 moves relative to the support table 300 in the direction in which the driving force is applied. The ball member 102 that supports the moving table 200 with respect to the support table 300 rotates by a frictional force generated between the moving table 200 and the moving table 200. For example, when the moving table 200 moves in the right direction in the drawing, the ball member 102 rotates clockwise.

  When the ball member 102 rotates and moves a certain amount with respect to the support table 300, the moving table 200 also moves the same amount with respect to the ball member 102. Therefore, the amount by which the moving table 200 moves with respect to the support table 300 is a value obtained by adding the moving amount of the ball member 102 and the moving amount of the moving table 200 with respect to the ball member 102. That is, the moving amount of the moving table 200 is twice the moving amount of the ball member 102.

  Since the movement amount of the ball member 102 is half that of the movement table 200, the ball member 102 moves relative to the movement table 200 in a direction opposite to the movement direction. The ball member 102 contacts the pressure transmission member 104 when the clearance amount between the ball member 102 and the pressure transmission member 104 is moved.

  When a driving force is further applied to the moving table 200, the ball member 102 moves further with respect to the moving table 200 and applies pressure to the pressure transmission member 104. A frustoconical coil spring 103 is arranged around the pressure transmission member 104 with a clearance. When the pressure transmission member 104 moves the clearance amount by the pressure of the spherical member 102, the pressure transmission member 104 contacts the truncated cone coil spring 103. The truncated conical coil spring 103 opposes the pressure from the ball member 102 transmitted through the pressure transmission member 104. That is, in the drawing, when the moving table 200 moves to the right, the ball member 102 moves to the left with respect to the moving table 200. The moved ball member 102 comes into contact with the pressure transmission member 104 to apply pressure to the truncated conical coil spring 103.

  The truncated cone coil spring 103 preferably has a small wire diameter and a sufficiently small initial transverse elastic modulus. Thereby, when the ball member 102 starts to apply pressure to the truncated conical coil spring 103, the drag force applied to the spherical member 102 from the truncated conical coil spring 103 can be reduced. That is, the frictional force between the ball member 102 and the pressure transmission member 104 can be reduced, and the running resistance of the moving table 200 can be reduced.

  The relationship between the moving amount of the moving table 200 and the running resistance will be described with reference to FIG.

  The X axis represents the amount of movement of the moving table 200, and the Y axis represents the running resistance of the moving table 200. The caster 100 according to the present embodiment is designed such that the maximum moving amount of the moving table 200 is 6 mm and the maximum running resistance is 3 g. A clearance of 0.5 mm is provided between each of the spherical member 102, the pressure transmission member 104, and the truncated conical coil spring 103. When a driving force is applied to the moving table 200, the ball member 102 moves by the amount of the clearance and contacts the pressure transmission member 104, and the pressure transmission member 104 contacts the truncated cone coil spring 103. In this process, the ball member 102 is not applied with a force from the truncated cone coil spring 103 via the pressure transmission member 104. Therefore, the moving table 200 moves without generating running resistance when moving the clearance amount.

  When the ball member 102, the pressure transmission member 104, and the truncated cone spring 103 come into contact, a drag force is applied from the truncated cone coil spring 103 to the pressure transmission member 104, and a frictional force is generated between the pressure transmission member 104 and the spherical member 102. . As described above, this frictional force can be suppressed small by the action of the truncated cone coil spring. Since the frictional force generates a running resistance, the running resistance of the moving table 200 increases when the truncated conical coil spring 103 is deformed according to the moving amount of the moving table 200 to increase the drag force on the pressure transmission member 104.

  A second embodiment will be described with reference to FIG. The description of the same configuration as that of the first embodiment is omitted.

  In the present embodiment, a coil spring 121 is used as the elastic member. As in the first embodiment, the rolling member is a spherical member 102 and is disposed inside a cylindrical pressure transmission member 104. A support member 120 protruding from the moving table 200 is provided around the pressure transmission member 104. The support member 120 has a cylindrical shape having a square cross section, and the length in the central axis direction is slightly longer than the radius of the spherical member 102. The length of the inner side is a value obtained by adding the free length of the two coil springs and the clearance to the outer diameter of the pressure transmission member 104. The support member 120 is disposed so as to protrude from the moving table 200 so that the central axis thereof is substantially coaxial with the central axis of the pressure transmission member 104 and to be spaced from the pressure transmission member 104 by a certain distance. One end of the coil spring 121 is attached to the inner surface of the support member 120 so that the shaft is perpendicular to the support member 120, and the other end is a pressure corresponding to the most protruding portion of the ball member 102 in the moving direction of the moving table 200. The part of the transmission member 104 is contacted.

  According to the present embodiment, the coil spring 121 can suppress the movement of the ball member 102 via the pressure transmission member 104, and the traveling resistance of the moving table 200 can be kept low.

  A third embodiment will be described with reference to FIG. Descriptions of configurations similar to those of the other embodiments are omitted.

  In the present embodiment, a leaf spring 131 is used as the elastic member. As in the first embodiment, the rolling member is a spherical member 102 and is disposed inside a cylindrical pressure transmission member 104. A support member 130 that protrudes from the moving table 200 is provided around the pressure transmission member 104 as in the second embodiment. The length of the inner side of the support member 130 is a value obtained by adding the free length of the two leaf springs 131 and the clearance to the outer diameter of the pressure transmission member 104. One end of a leaf spring 131 is attached to the inner surface of the support member 130, and the other end contacts a portion of the pressure transmission member 104 corresponding to the most protruding portion of the ball member 102 in the moving direction of the moving table 200.

  According to the present embodiment, the leaf spring 131 can suppress the movement of the ball member 102 via the pressure transmission member 104, and the traveling resistance of the moving table 200 can be reduced.

  The rolling member may be a cylindrical columnar member. The moving table is movable in one direction, and a flat plate-shaped pressure transmission member is provided in each moving direction of the moving table in the cylindrical member. An elastic member is attached between the pressure transmission member and the moving table to suppress the movement of the cylindrical member with respect to the moving table.

  Note that three or more casters 100 may be provided on the support table 200.

  The coil spring 109 may be fixed to the support table 300 instead of the moving table 200. The traveling resistance can be reduced by reducing the weight of the moving table 200.

  The magnet 202 may be provided on the support table 300, and the moving table 200 may be made of a magnetic material. The moving table 200 can be restrained in the vertical direction with respect to the support table 300.

It is a perspective view of the table with a caster in a 1st embodiment. It is sectional drawing in the II-II line in FIG. 1 of a table with a caster. It is the partial cross section figure which showed the cross section of the caster part. It is a perspective view of the table with a caster which abbreviate | omitted the nut which fixes a caster. It is a top view of the caster part seen from the moving table side. It is the fragmentary sectional view which showed the cross section of the caster part at the time of the movement of a movement table. It is the graph which showed the relationship between the movement amount of a movement table, and driving resistance. It is a top view of the caster part in 2nd Embodiment. It is a top view of the caster part in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Table with casters 100 Casters 102 Rolling member 103 Elastic member 104 Pressure transmission member 105 Support member 106 Nut 200 Moving table 202 Magnet 300 Support table

Claims (18)

A caster that supports a movable body so as to be movable in one or two directions with respect to the support,
The movable body and the support body have opposing surfaces facing each other,
A rolling member that has a circular cross-section in a plane parallel to a direction in which the moving body moves and is perpendicular to the facing surface, and supports the moving body and the supporting surface in contact with the facing surface;
A caster made of an elastic member that suppresses the movement of the rolling member in the moving direction of the moving body.   The said elastic member suppresses a movement of the said rolling member by contacting the said rolling member in the site | part most projected of the said rolling member in the moving direction of the said mobile body. The caster described.   The caster according to claim 1, wherein a pressure transmission member is provided between the rolling member and the elastic member.   The caster according to claim 1, wherein the caster supports the movable body movable in one direction, and the rolling member has a cylindrical shape.   The caster according to claim 4, wherein a pressure transmission member is provided between the rolling member and the elastic member.   The caster according to claim 1, wherein the rolling member has a spherical shape.   The caster according to claim 6, wherein a pressure transmission member is provided between the rolling member and the elastic member. The pressure transmission member has a cylindrical shape whose axial length is shorter than the diameter of the rolling member and whose inner diameter is longer than the diameter of the rolling member, and the central axis is provided to be perpendicular to the support. And
The caster according to claim 7, wherein the rolling member is disposed inside the pressure transmission member.   The caster according to claim 1, wherein the elastic member is a coil spring.   The caster according to claim 9, wherein the coil spring is a frustoconical coil spring.   The caster according to claim 9, wherein the axial length of the coil spring is substantially the same as the radius of the rolling member.   The large-diameter end portion having the largest diameter in the coil spring is fixed to the movable body or the support body so that a central axis of the coil spring is perpendicular to the movable body. Casters. A pressure transmission member is provided between the rolling member and the coil spring,
The pressure transmission member has a cylindrical shape whose axial length is shorter than the diameter of the rolling member and whose inner diameter is longer than the diameter of the rolling member, and the central axis of the coil spring is substantially coaxial. Provided inside the coil spring,
The caster according to claim 12, wherein the rolling member is disposed inside the pressure transmission member. The mobile body or the support body includes a support member that protrudes around the rolling member in a moving direction of the mobile body with a certain distance,
The coil spring is provided between the rolling member and the support member, and moves by moving the rolling member by contacting the rolling member at the most protruding portion of the rolling member in the moving direction of the moving body. The caster according to claim 1, wherein the caster is suppressed.   The caster according to claim 1, wherein the elastic member is a leaf spring. The mobile body or the support body includes a support member that protrudes around the rolling member in a moving direction of the mobile body with a certain distance,
The leaf spring is provided between the rolling member and the support member, and comes into contact with the rolling member at the most projecting portion of the rolling member in the moving direction of the moving body. The caster according to claim 15, wherein movement is suppressed.   The caster according to claim 1, wherein the support is made of a magnetic material, and a magnet is attached to the movable body.   The caster according to claim 1, wherein the movable body is made of a magnetic material, and a magnet is attached to the support body.

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